Dear Doctor: I have been taking fish oil capsules daily over the last five years. Is there any benefit in doing this?

Dear Reader: The short answer is "maybe." Scientists have shown that societies with higher fish intake have lower rates of heart disease. The belief is that this benefit comes from fish oil. Fish oil contains substances known as long-chain fatty acids (omega-3 fatty acids), specifically DHA, DPA and EPA, with many health benefits. These fatty acids help lower blood triglyceride levels; lower blood pressure (by 1.5 to 4 points); and have an ability to help the heart relax so that blood flows more easily into its chambers. Furthermore, the omega-3 fatty acids in fish oil have also been linked to a slightly slower heart rate and to a decrease in inflammation.

Small studies have shown that fish oil may be linked to a slight reduction in the formation of plaque in the arteries that supply the heart, but evidence of its ability to reduce the rates of heart attack hasn't been as robust or as statistically significant.

One fish oil finding that was indeed statistically significant was from a large study published in the Journal of the American Medical Association in 2006. That study linked fish oil intake of 250 milligrams per day to a 36 percent reduction in rates of sudden cardiac death. That amount -- 250 mg of fish oil -- equals 1 to 2 servings of fish per week.

One other property that fish oil may have is an ability to reduce electrical excitability of the heart. That reduced excitability may decrease the heart's chances of going into an abnormal rhythm, which can lead to death. Furthermore, among people who have had a heart attack, 1 gram of fish oil per day has been linked to a significant decrease in death rates. The benefits of fish oil have been seen as early as four months after a heart attack and even as late as 36 months after a heart attack. Again, this appears to be related to fish oil's potential protective effect against abnormal heart rhythms after a heart attack.

Fish oil hasn't been shown to decrease the chance of a stroke. Nor has it been shown to decrease the risk or incidence of cancer. In fact, some studies have shown a correlation between fish oil and prostate cancer, but other studies have failed to support that connection.

In summary, fish oil does appear to decrease the chance of sudden cardiac death, but you don't need to take capsules to see this benefit. Eating fish twice a week can do that.

Before you turn to eating tuna fish from a can, keep in mind that tuna has much less omega-3 fatty acids than Atlantic salmon, mackerel or herring. If you don't care for fish, taking 1 gram of a fish oil supplement twice a week will likely yield a benefit. If you've had a heart attack, consider taking 1 gram of fish oil a day.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: Our young son fell off his skateboard recently, and the items my wife and I needed to tend to his cuts and scrapes were scattered throughout the house. Now we want to assemble a home first-aid kit. What should it contain?

Dear Reader: Great idea! A well-stocked first-aid kit is an important safety feature for every home. And while first-aid kits are available for purchase, you can easily put one together yourself.

Take an afternoon to evaluate your family needs, make a list, then hit your local drugstore. With just a little bit of planning, you'll be ready to handle the minor bumps and mishaps of everyday life at a moment's notice.

With a home first-aid kit, you're preparing to deal with three basic types of medical issues -- injury, infection and allergy.

Everyday injuries include scrapes, cuts, splinters, burns, sprains and stings. Infections may range from an inflamed wound to fever, a sore throat or the flu. You'll also want to be prepared for common allergic reactions such as the rash from poison oak and poison ivy, and itching and swelling from insect stings.

It's important that if anyone in your family has severe food allergies or a respiratory condition such as asthma, you stock a backup of the appropriate medication. Mark each item with its expiration date and replace as needed. It's a good idea to keep a separate checklist, which will make it easy to know when it's time to replace that inhaler or EpiPen.

So how do you build a first-aid kit?

Start with a container such as a plastic storage tub, a tackle box or a tote bag with separate compartments. It should be easy to open, easy to carry, and have enough room for everything to be organized and recognizable at a glance.

Delegate one compartment for personal items -- those allergy medications we talked about or backup doses of any other vital medications your family members may need. You'll also want to include a list of emergency phone numbers.

For a family of four to deal with common emergencies, you should have:

-- 2 absorbent compress dressings

-- 25 adhesive bandages of assorted sizes

-- 1 adhesive cloth tape

-- Antibiotic ointment and antiseptic wipes

-- Ibuprofen

-- Acetaminophen

-- An instant cold compress

-- Non-latex gloves to be worn when dealing with blood or bodily fluids

-- Hydrocortisone ointment

-- A pair of scissors and a set of tweezers

-- A 3-inch and a 4-inch roller bandage

-- 10 sterile gauze pads (3 by 3 inches and 4 by 4 inches)

-- An oral thermometer that is not glass and does not contain mercury

-- 2 triangular bandages

-- A good first-aid instruction booklet

Rather than in the bathroom, where humidity may affect the contents, keep your first-aid kit in the kitchen. It's also wise to consider a version of this kit for your car.

Finally, read through the first-aid instruction booklet on a regular basis. You don't want to be holding a page open while you're trying to bandage a sprained ankle!

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: If I received the flu shot in September, will I still be protected from the flu in March?

Dear Reader: That's a very good question -- and the answer depends, in part, on your current health.

The flu season normally lasts from November to March, but it can begin in October and even end in May. The injected influenza vaccine, which contains three to four inactivated viruses from the prior flu season, spurs the formation of antibodies to help your body fight off influenza if you're exposed. It takes about two weeks after the vaccine for your body to produce sufficient protective antibodies.

If you are a young, healthy person under 50, you're more likely to get a good immune response from the vaccine -- and also more likely to have an immune response that lasts six to 12 months. You'll also have a greater and longer-lasting immune response if you get the flu vaccine every year. So if you got your shot in September, you should have immunity that lasts throughout the flu season.

If you're older than 50 and have diabetes, cancer, or kidney or liver failure, your ability to mount a good response from the vaccine decreases. So six months after your vaccination, you may not have sufficient antibodies to ward off the flu. This has been shown specifically for the H1N1 influenza virus. If you received the vaccine on Sept. 1, you may be less protected by April of the following year against H1N1.

This decreased immunity is especially pronounced in people over the age of 65. It decreases even further among those over 65 who have chronic illnesses.

Some pharmacies have been administering the flu vaccine as early as the middle of August. This isn't necessarily a bad thing for someone older than 65 or someone with chronic illnesses, because you still get immunity from the vaccine that should last through much of the flu season. Still, it's probably better to wait until at least the middle of September to get the flu vaccine just to ensure you're protected for as much of the flu season as possible.

Finally, it's especially important to get yearly flu vaccines if you are: older than 60; between the ages of 6 months and 4 years; have chronic illnesses; or are pregnant. The flu is especially risky for these groups.

While imperfect, the flu vaccine is the best way our society has found to decrease the death rates and the long-term complications from a potentially fatal disease that causes anywhere from 3,300 to 49,000 deaths per year in the United States.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)